Masaaki Iwahashi
Wakayama Medical University
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Featured researches published by Masaaki Iwahashi.
Fertility and Sterility | 2000
Masaaki Iwahashi; Yasuteru Muragaki; Akira Ooshima; Ryosuke Nakano
OBJECTIVE To identify type VI collagen expression in human ovarian follicles during follicular growth. DESIGN In vitro experiment. SETTING Department of Obstetrics and Gynecology, Wakayama Medical College, Japan. PATIENT(S) Regularly cycling women who underwent adnexectomy. INTERVENTION(S) Immunohistochemistry and in situ hybridization for human type VI collagen. MAIN OUTCOME MEASURE(S) Expression of type VI collagen. RESULT(S) Expression of type VI collagen was observed in the theca cell layers during folliculogenesis, whereas no expression of type VI collagen was observed in the granulosa cell layers at the mRNA and protein levels. As the follicles grew, immunostaining for type VI collagen became intense in the theca cell layers, especially the theca externa. In preovulatory follicles, however, weak, fragmented, or discontinuous immunostaining of the theca cell layers was observed. This fragmented or discontinuous immunostaining was evident predominantly in the apical area of preovulatory follicles rather than in the basal area. CONCLUSION(S) Type VI collagen is present in the theca cell layers of follicles during folliculogenesis and plays an important role in interactions between the theca cells and extracellular matrix. These interactions may lead to changes in the shape, proliferation, migration, or differentiation of follicular cells during follicular development, maturation, and ovulation.
International Journal of Radiation Oncology Biology Physics | 1995
Koh Tsuji; Ryusaku Yamada; Mamoru Kawabata; Kiyoshi Mitsuzane; Morio Sato; Masaaki Iwahashi; Shunya Kitayama; Ryosuke Nakano
PURPOSE The effect of local injection of anticancer drugs by balloon catheter, i.e., balloon occluded arterial infusion (BOAI), on the prognosis of cervical cancer treated with radiotherapy were retrospectively estimated. METHODS AND MATERIALS Sixty-five patients with cervical cancer (Stage I-IV) treated by irradiation were included in the study. Among the 65 cases, 2 were in Stage I, 13 in Stage II, 40 in Stage III, and 10 in Stage IV. Patients who received surgical resection were excluded. Thirty-nine patients received BOAI and 44 received brachytherapy. Twenty-six patients were not indicated for BOAI because of insufficient renal function, hepatic complications, hematological complications, and refusal from the patients. Cisplatin (0.9-1.7 mg/kg), Adriamycin (0.7-0.9 mg/kg), and Pepleomycin (0.4-0.6 mg/kg) were administered simultaneously into the bilateral internal iliac arteries by BOAI. External irradiation was given by 10 MV x-ray. Total dose administered to the regional lymph nodes by the external irradiation was 48.3 +/- 8.7 Gy. Radium was used at brachytherapy. The dose delivered by the brachytherapy at point A was 45.3 +/- 14.9 Gy. Patients without brachytherapy received 26.1 +/- 19.1 Gy of boost irradiation by the external photon beam. The survival probabilities of the patients were calculated by Kaplan-Meier method. RESULTS The 5-year survival rates of the Stage III patients with and without BOAI were 53 +/- 13% and 24 +/- 18%, respectively (p = 0.036). By multivariate analyses using Coxs proportional hazard model, stage and BOAI were selected as significant predictors of the prognosis. Transient bone marrow suppression was observed in about half of the patients with BOAI. No significant increase of the incidence of the late radiation damage by BOAI in rectum or in urinary bladder was observed. CONCLUSION Balloon occluded arterial infusion of anticancer drugs may improve the prognosis of the patients with cervical cancer without increasing the incidence of the late radiation damage. A larger scale prospective randomized study is desired.
Fertility and Sterility | 2011
Masaaki Iwahashi; Yasuteru Muragaki
Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that the ratios of type I and type V collagen expression were significantly increased in the leiomyoma tissues at the protein level, as compared with those in the normal myometrium tissues through the menstrual cycle. These results suggest that increased expression of type I and type V collagen might play a role in the pathogenesis of uterine leiomyoma.
Pathology International | 1995
Masaaki Iwahashi; Mareo Yamoto; Kazuya Yamashita; Ryosuke Nakano; Akira Ooshima
A 63 year old woman presented with a giant abdominal tumor. Ultrasonography, computerized tomography and drop infused pyelography revealed a suspected retroperitoneal tumor. The tumor was removed surgically and weighed 2800g. The pathological diagnosis of the tumor was schwannoma. Strong immunohistochemical staining specific for type IV collagen and laminin was observed in the tumor, and these components were localized in the pericellular region of Schwann cells. The serum levels of these antigens, as determined by radio‐immunoassay, were very high before the operation but decreased rapidly thereafter.
Reproductive Biology and Endocrinology | 2012
Masaaki Iwahashi; Yasuteru Muragaki; Kazuhiko Ino
BackgroundTo investigate the role of prolyl hydroxylase (PH), a key enzyme of collagen synthesis, in human uterine leiomyoma, PH expression was determined in the normal uterine myometrium and the leiomyoma tissues during the menstrual cycle.MethodsThe tissues were obtained from 40 regularly cycling women (aged 29 to 53 yr) who were undergoing abdominal hysterectomy for symptomatic uterine leiomyoma. Immunohistochemistry for human PH with specific monoclonal antibody was used for analysis.ResultsImmunohistochemical staining for PH revealed intense staining of leiomyoma cells in the uterine leiomyoma throughout the menstrual cycle, as compared with the adjacent normal myometrium. In the secretory phase, weak or no immunostaining for PH was detected in the normal myometrial tissues.ConclusionsThese results suggest that increased expression of PH might play an role in the physiology of uterine leiomyoma during the menstrual cycle.
Fertility and Sterility | 2011
Masaaki Iwahashi; Yasuteru Muragaki
Immunohistochemical staining for human prolyl hydroxylase revealed intense staining of the human corpora lutea (CL) parencyma during early pregnancy compared with those in the menstrual cycle. These results suggest that human prolyl hydroxylase might play an important role in determining the physiology and structure of the CL during the menstrual cycle and early pregnancy.
Ultrasound in Obstetrics & Gynecology | 2004
Shigetaka Yagi; Sawako Minami; N. Otani; Masaaki Iwahashi; N. Ooba; Naohiko Umesaki
The Silver-Russell syndrome (SRS) is characterized by severe intrauterine growth restriction, with a preserved head circumference, leading to a lean body habitus and short stature. Facial dysmorphism and asymmetry are considered typical features of the syndrome, although the range of phenotypic variance is unknown. A woman was transferred to our hospital due to decreased maternal serum α-fetoprotein (0.185 MoM), human chorionic gonadotrophin (0.128 MoM) and unconjugated estriol (0.775 MoM) at 16 weeks of gestation. Initial ultrasonographic findings showed oligohydramnios. But serial antenatal sonographic findings showed severe asymmetric intrauterine growth restriction (preserved head circumference, small abdominal circumference, and short femur) and both hydronephrosis with progressive oligohydramnios. Cytogenetic studies with GTG-banding by amniocentesis showed 46 XX, inv (9) (p11q13) and fetal karyotype was in paternal origin. On past history, the previous sibling of the fetus also showed severe asymmetric intrauterine growth restriction (31 weeks sized biparietal diameter, 25 weeks sized abdominal circumference, and 28 weeks sized femur length) with oligohydramnios at prenatal ultrasonography. After birth, she was diagnosed as SRS due to large cranium, broad forehead, microretrognathia, clinodactyly, and short philtrum with low birth weight and postnatal growth below to 2 SD from the mean. She died at 10 months of her age. At 26 weeks of gestation, fetal death in uterus was diagnosed and the fetus was delivered by labor induction. Autopsy findings showed asymmetric low birth weight (less than 5th percentile) with characteristic small triangular face, low set ears, clinodactyly and downward slanting corners of mouth. On the basis of these evidences, we diagnosed that this case was also SRS. We report a case of familial Silver-Russell syndrome with literatures.
The Journal of Clinical Endocrinology and Metabolism | 2003
Masaaki Iwahashi; Yasuteru Muragaki; Akira Ooshima; Naohiko Umesaki
The Journal of Clinical Endocrinology and Metabolism | 1996
Masaaki Iwahashi; Yasuteru Muragaki; Akira Ooshima; Ryosuke Nakano
Experimental and Therapeutic Medicine | 2011
Masaaki Iwahashi; Yasuteru Muragaki; Makoto Ikoma; Yasushi Mabuchi; Aya Kobayashi; Yuuko Tanizaki; Kazuhiko Ino